Furthermore, one study showed that ALS patients on average possess fewer SMN2 copies, while having one SMN1 copy is associated with increased ALS susceptibility (Veldink et al., 2005), although this link is not straightforward (Blauw et al., 2012; Corcia et al., 2012; Wang X.-B. The gene discussed is SMN2; the disease is amyotrophic lateral sclerosis.